Transistors - Bipolar (BJT)

Transistors - Bipolar (BJT) - Single

Part Number	Description / PDF	Quantity
2N6259 NTE Electronics, Inc.	TRANS NPN 150V 16A TO3	433
NTE2329 NTE Electronics, Inc.	TRANS PNP 200V 15A TO3PBL	64
NTE194 NTE Electronics, Inc.	TRANS NPN 160V 600MA TO92	5080
NTE199 NTE Electronics, Inc.	TRANS NPN 50V 100MA TO92	7768
MJ10001 NTE Electronics, Inc.	T-NPN SI- PO DARL SW	224
NTE2300 NTE Electronics, Inc.	TRANS NPN 800V 5A TO3P	57
MJE15031 NTE Electronics, Inc.	TRANS PNP 150V 8A TO220AB	1329
2N6667 NTE Electronics, Inc.	T-PNP SI-GEN PUR AMP	708
2N5430 NTE Electronics, Inc.	TRANS NPN 100V 7A TO66	82
NTE61 NTE Electronics, Inc.	TRANS PNP 140V 20A TO3	36
2N3585 NTE Electronics, Inc.	TRANS NPN 300V 2A TO66	16
NTE285MP NTE Electronics, Inc.	TRANS PNP 180V 16A TO3	5
2N3390 NTE Electronics, Inc.	TRANS NPN 25V 500MA TO92-3	14
TIP34C NTE Electronics, Inc.	TRANS PNP 100V 10A TO218	405
NTE2407 NTE Electronics, Inc.	TRANS PNP 60V 600MA SOT23	2923
NTE37MCP NTE Electronics, Inc.	TRANS PNP 140V 12A TO3P	0
NTE2525 NTE Electronics, Inc.	T-PNP SI HI CURRENT SW TO-126N	834
TIP48 NTE Electronics, Inc.	HIGH VOLTAGE, SILICON NPN TRANSI	1000

Transistors - Bipolar (BJT) - Single

1. Overview

Bipolar Junction Transistors (BJTs) are three-terminal semiconductor devices that use both electron and hole charge carriers. They form the foundation of analog electronics through their ability to amplify signals and control current flow. BJTs remain critical in modern electronics for applications ranging from audio amplifiers to power management circuits, offering superior linearity and robustness in switching operations.

2. Main Types & Functional Classification

Type	Functional Characteristics	Application Examples
NPN Transistor	Majority carriers: electrons. Requires positive base current for conduction.	Low-noise amplifiers, digital logic circuits
PNP Transistor	Majority carriers: holes. Conducts with negative base current.	Power supply circuits, motor controllers
High-Frequency BJT	Optimized for RF/microwave signal amplification (f_T > 100 MHz)	Wireless communication systems, radar
Power BJT	High current/voltage ratings (I_C > 1A, V_CE > 50V)	Switch-mode power supplies, motor drives

3. Structure & Composition

BJTs consist of three doped semiconductor regions forming two p-n junctions:

Emitter: Heavily doped region emitting charge carriers
Base: Thin, lightly doped middle region controlling carrier flow
Collector: Moderately doped region collecting carriers

Manufactured using silicon (common) or germanium (historic) with planar processing technology. The structure forms either NPN (n-type emitter/base/collector) or PNP configuration, with metal contacts for external connections.

4. Key Technical Specifications

Parameter	Description	Importance
Current Gain (h_FE)	Ratio of collector to base current (10-1000)	Determines amplification capability
Transition Frequency (f_T)	Frequency at which current gain drops to 1	Limits high-frequency performance
Max Collector Current (I_Cmax)	Maximum allowable continuous collector current	Defines power handling capability
Breakdown Voltage (V_CEO)	Max voltage between collector and emitter	Prevents device failure under stress
Saturation Voltage (V_CEsat)	Voltage drop in fully conducting state	Affects power efficiency in switching

5. Application Areas

Consumer Electronics: Audio amplifiers, LED drivers
Automotive: Engine control units, electric vehicle inverters
Industrial: PLCs, motor controllers
Telecommunications: RF power amplifiers, fiber optic transceivers
Aerospace: Avionics systems, satellite transponders

6. Leading Manufacturers & Products

Manufacturer	Product Series	Key Specifications	Typical Use
ON Semiconductor	2N3904	hFE: 100-300, fT: 300 MHz	General-purpose switching
Infineon	BC547	VCEO: 50V, ICmax: 100mA	Analog signal amplification
STMicroelectronics	2SD2656	ICmax: 15A, VCEO: 80V	Power inverter applications
Diodes Inc.	BFR93A	fT: 10 GHz, Noise Figure: 2dB	High-frequency front-end amplifiers

7. Selection Guidelines

Determine operating frequency: Select fT > 3 target frequency
Power requirements: Ensure Icmax and VCEO exceed circuit requirements by 20%
Thermal considerations: Calculate power dissipation (P=V_CE I_C)
Package type: TO-92 for low power, TO-220 for high-power applications
Environmental factors: Consider temperature ratings for industrial/military use

8. Industry Trends

Future developments include:

High-frequency BJTs operating beyond 100 GHz for 6G communication
Integrated BJT-MOSFET hybrid devices (BiCMOS) for mixed-signal applications
Wide-bandgap materials (SiC/GaN) for higher power density
Miniaturization through chip-scale packaging
Improved thermal management solutions for automotive applications